public function testGetDescendantsAndSelf()
{
$root = new Node('r');
$root->addChild($a = new Node('a'))->addChild($b = new Node('b'));
$a->addChild($c = new Node('c'))->addChild($d = new Node('d'));
$b->addChild($e = new Node('e'))->addChild($f = new Node('f'));
$this->assertEquals([$a, $c, $d], $a->getDescendantsAndSelf());
$this->assertEquals([$b, $e, $f], $b->getDescendantsAndSelf());
$this->assertEquals([$root, $a, $c, $d, $b, $e, $f], $root->getDescendantsAndSelf());
}
